Bobcat T770 track motor problem?

[daren99]

Hey guys,

My T770 right side track has been acting up as is kind if pulsating or dragging and yesterday it pretty much quit turning, had enought to get it on a trailer but barely. Before it quit the hydraulic pressure gauge bottomed out. No lights or alarms but the guage fell, so I shut it off. I went and got the trailer and stated it up again, the guage was still down so I gave it a little throttle and the guage popped back up again so I got it on the trailer and it dropped again. The machine didn't act any different when the guage was normal or bottomed out. The oil doesn't seem to have any filings in it. My assumption is track motor but not 100% sure. Any ideas? Thank you

 

[bobcan]

Hmmm.. Quick thought: How long/many hours since you have replaced the Case Drain Filters (wee brass in-line ones at/near motors) and also have you serviced the 'far too expensive' High Pressure Oil in the Drives as you should too..?? The second one would NOT cause the condition I do not believe, but the first I believe likely might, if plugged up.. a Service Manual is your friend, maybe $50 worth of Parts and an hour of time and you could be happy again, I hope.. Good Luck

 

[daren99]

The t770 doesn't have the case drain filter, it now runs through the fan filter. I pulled that and cut it open and it looked good. I have to check the system pressure to rule out other hydraulic problems and the sending unit and know for sure but, I'm about 99% sure it's bypassing through the drive motor. I need to do the 1000 hour system flush also. Thanks for the reply.

 

[bobcan]

Ahha _ Good to know _ seems like you are on the way to a solution I hope then, I would 'hope from past experience' that a Drive Motor could not/ would not come apart internally without leaving some signs of troubles, but not at all that specifically wise on that machine, as evidenced by my 'Case Drain' thoughts.. Ha!!

Once again, I hope it is a simple and painless fix, once found.. Stay Well there!!

 

[daren99]

I may be wrong but I was told that the drive motors from bobcat and from aftermarket sources are basically the same, as the parts are proprietary to bobcat so the only difference is who puts them in. The aftermarket cost seems to be about half of factory rebuilds. The warranties are 6-12 months also. The aftermarket sprockets last longer then the newer bobcat versions, mine are original and have about 1300 hours on them and they are shot. I was told they should last at least 2500 hours on the average.

 

[Equip Junkie]

I have had 3 drive motors go on my machine. First time at 32 hours from new. Second time at 64 hours from new. After the second time, they found out that the hydraulic pump was having issues and sending metal into the drive motor. The last time was at just over 1000 hours. I had just had a 1000 hour service done where they drained and refilled the "expensive" High pressure oil. 4 hours after the service, my drive stopped working. When they took it apart, there was no oil and the fill screw was loose. Either the mechanic never filled it, or it lost oil through the fill screw. In all cases, they covered it under warrantee, including the large bill for the hydraulic pump. I have them change the high pressure oil sooner than the book asks because I am concerned about it. They check it at 250 hours and replace at 500 hour. I use the machine for mulching so the hydraulic oil gets changed out sooner too. I have talked to the mechanic and he mentioned that the seal on the back side that holds in the High pressure oil can allow a slow leak. If it goes unnoticed due to dirt packing in the area and the small oil amount, it can run dry and then bad things happen fast. That is why I get them to check it often. That way if there is any missing, then they look for a leak in the seal. I hope this isn't your issue, because it isn't cheap to fix. I love my T770. It has had issues, but the dealer has been pretty awesome so far.

Equip